When was the prairie ecozone created

T he Prairies Ecozone is often characterized as flat, rural, wheat- and oil-producing, or cold. The terms describe significant aspects of the environment and the economy but understate its diversity and recent evolution. The relief is typically subdued, consisting of low-lying valleys and plains sloping eastward. High elevations result in a climate that is cooler and more moist than the surrounding dry grasslands. Vestiges of a montane forest, dominated by lodgepole pine, that once extended all the way to the Rocky Mountains remain to this day: this is the Cypress upland.

Many small wetland areas, or sloughs, occur throughout the Prairie Ecozone. In the more humid parts, these sloughs tend to be more permanent, the water is relatively fresh, and they are ringed by willows and trembling aspen.

In drier parts of the ecozone, however, the sloughs are less permanent and more saline, and the transition from the wetland to the grassland is a sharp one. Most freshwater wetlands are characterized by emergent vegetation such as sedges, bulrushes, cattails, and reed grasses on their margins. In the open water, submerged growth of pondweeds, yellow watercrowfoot, and greater bladderwort may be present. Saline wetlands do not have a marginal ring of willows, but rather have shorelines heavily encrusted with white salts and usually bare of vegetation except for a few salt-tolerant plants like red samphire.

Salt-tolerant grasses, such as seaside arrow-grass and alkali grass, grow at the margin of the salt crusts. Historically, the prominent species on the prairie was the Bison. The Pronghorn antelope, though an animal of the open plains, ranged well into the parkland. Elk grazed on the grassland around the edges of aspen groves.

The wolf was the main predator of the ungulates. Settlement and widespread cultivation of the grasslands has caused some species to come near the brink of extinction as in the case of bison or to currently occupy a small portion of their former range.

An abundance of assorted mice and voles inhabit the matted vegetation in unburned or ungrazed grassland. The thirteen-lined ground squirrel also prefers longer grasses. The northern pocket gopher spends most of its life underground, feeding on succulent roots in pastures and haylands; its mounds of soil become an annoyance during haying.

Coyote, red fox, and the re-introduced swift fox feed chiefly on Rodents , Birds , and insects. The badger feeds predominantly on ground squirrels, which it captures by digging see Carnivores.

The snowshoe hare inhabits aspen groves during the day, emerging to feed at night, while the white-tailed jack rabbit frequents pastures, cultivated fields, and open, arid prairie, seldom penetrating wooded areas except as shelter from blizzards see Hares and Rabbits.

The striped skunk reaches its highest densities in agricultural areas, and the woodchuck has also prospered as a result of agricultural and Forestry practices. Characteristic grassland birds include western meadowlark, Horned Lark , upland sandpiper, and chestnut-collared longspur. The vesper sparrow, clay-colored sparrow, chipping sparrow, and sharp-tailed grouse are more abundant on prairie adjacent to woodland.

In the winter, large flocks of snow bunting and common redpoll frequent grasslands, fields, and road edges, feeding on seeds of forbs and grasses exposed above the snow. Reptile species are most numerous in the prairie, preferring the warmth of a dry arid region. Fourteen species of Reptiles occur here, 11 of which occur in the mixed grassland. An additional three species of Amphibians occur in the prairie as compared to the boreal plain. Human Activity.

The Prairies Ecozone is now typified by large tracts of flat to rolling plains. A great variety of surface landforms, from hummocky lands to deeply entrenched river valleys, also exist. Most of the major rivers have their origin in the Rockies. These rivers flow east across the ecozone and are fed by rainfall, snowmelt, and glacial runoff at their headwaters.

Many smaller rivers and streams of the Prairies Ecozone have highly variable flows and are often dry for long periods. The result is a pronounced, subhumid to semi-arid climate. Winters are very cold. Trees found in the Prairies include white spruce, black spruce, balsam fir, tamarack, water birch , Bebb willow, peachleaf willow, wolf willow, lodgepole pine, box elder, choke cherry, black cottonwood, eastern cottonwood , bur oak, trembling aspen, and balsam poplar.

Just a few of the other plants that grow here are spear grass, wheat, blue grama grass, sagebrush, yellow cactus, prickly pear, buckbrush, chokecherry, Saskatoon berry bush, alkali grass, wild barley, red sampire, sea blite, Parry oat grass, June grass, yellow bean, sticky geranium, bedstraw, chickweed, needle grass, thread grass, snowberry, American silverberry, rose, silverberry, dryland sedge, black hawthorn, greasewood, plains larkspur , death camas, wild lupine, smooth aster, prairie sedge, and cattail.

Animals The widespread alteration of the natural habitat has resulted in diminished populations and ranges of many animals, and the Prairies contain a disproportionate number of threatened and endangered species. Mammals The only large carnivore in the Prairies is the black bear. Large herbivores include whitetail deer a recent invader , mule deer , pronghorn antelope , elk , and moose. Small carnivores include coyote , badger , red fox , longtail weasel , mink , river otter , black-footed ferret , and striped skunk.